Animating with Action Sets and Action Constraints
Here are some finished constraints.
Below Bone.Left has an action constraint.



Below Bone.Right has an action constraint.



In both cases above


[Bone.Control] of the armature is the target bone.
X location is used.
The action name [Armature.C006Action]
All settings are the same because we used one armature and this is intended to be a simple example.


In pose mode keyframes were inserted on Bone.left and Bone.Right on frames 1 and 20.  Inserting keyframes created actions with a name we can use in the action constraint panel.  When Bone control is moved in the X direction here is the result.



The action name came from the DopeSheet/Action Editor Window



In the image above the action name was created. Saved to the Abstract Vault by clicking the letter F next to the name.  The action name is remembered for the constraints.  The action is removed from the armature. Repeat. The action is removed from the armature. If you leave it by mistake the action will dominate the [action constraint] and the flexibility you want will not function.